Screens are used in water wells to retain sand and gravel in the well hole, and prevent debris from being pumped from the well. The screen aids in the proper development of the well structure. In some cases, these wells can be deep underground. When the screens are installed, there is often a great deal of weight hanging from the screen as it is lowered into the well bore. This can cause the screen to fracture or separate, releasing other screen or piping that is attached to the screen into the well. When this problem occurs, the well must be redrilled or extreme measures taken to remove the fractured portion of the screen cylinder.
Screens with higher weight or geomechanical pressure have been traditionally made from heavier construction. The screen may include wire spirally wrapped and welded to a set of longitudinal rods. The tensile or weight bearing strength of the screen is then dependent at least in part on the strength of the longitudinal rods. Larger rods may be used to provide higher screen strength. While the rods themselves may be able to resist the overall loading, the load capacity of the assembly is also dependent on the bond between the screen rods and any fittings that are used to attach the screen to pipes or additional screens. These fittings are often threaded male or female ends welded to each end of the screen cylinder. With a conventional screen, the maximum weld area for welding rods to the fitting at the end of the screen may be equivalent to the cross sectional area of the longitudinal rods. Considering that the type of welds normally used to attach the screen to the fittings does not allow for full use of the available weld area, the strength of the screen for structural resistance may be limited by this joint.